CVE-2026-9803
Fixed upstream EPSS <1%CVSS 5.3
A flaw was found in Keycloak's ClientRegistrationAuth component. A remote unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with a malformed 'Authorization: Bearer' header to any client registration endpoint. This can lead to an ArrayIndexOutOfBoundsException, causing the server to return an HTTP 500 error and resulting in a Denial of Service (DoS) for the affected service.
Products: Red Hat build of Keycloak 26.4, Red Hat build of Keycloak 26.4.13, Red Hat build of Keycloak 26.6, Red Hat build of Keycloak 26.6.3
Fixed upstream
| Ecosystem | Package | Fixed in |
|---|---|---|
| Maven | org.keycloak:keycloak-services | no fix |
| Maven | org.keycloak:keycloak-services | 26.6.3 |
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Chainguard | keycloak-26.4 | no fix |
| Chainguard | keycloak-26.4-iamguarded-compat | no fix |
| Chainguard | keycloak-26.5 | no fix |
| Chainguard | keycloak-26.5-iamguarded-compat | no fix |
| Chainguard | keycloak-fips-26.4 | no fix |
| Chainguard | keycloak-fips-26.4-iamguarded-fips | no fix |
| Chainguard | keycloak-fips-26.5 | no fix |
| Chainguard | keycloak-fips-26.5-iamguarded-fips | no fix |
| Chainguard | request-9047-keycloak-fips-26.4 | no fix |
| Chainguard | request-9047-keycloak-fips-26.4-iamguarded-fips | no fix |
| Chainguard | request-9047-keycloak-fips-26.5 | no fix |
| Chainguard | request-9047-keycloak-fips-26.5-iamguarded-fips | no fix |
| Wolfi | keycloak-26.4 | no fix |
| Wolfi | keycloak-26.4-iamguarded-compat | no fix |
| Wolfi | keycloak-26.5 | no fix |
| Wolfi | keycloak-26.5-iamguarded-compat | no fix |